Thermostatic switch



April 8, 1947.

R. H. JORDAN 2,418,647

THBRMOSTATIC SWITCH Filed May 19, 1944 2 Sheets-Sheet 1 V gm! 3 E J j 5E as f w 32 g 4! 43 50 2 g: Jyd

40 J I m/(ion 24 29 Inuldfion Z2 2 INV TOR. BY W H. M

A ril 8, 1947. R. a JORDAN 7 'I'HRRQOSTATIG SIITCH rum m 19. 1944 a Shw-sung;

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j 2 I iliustmte e type at thermostatic switch with which invention willoperate The thermostatic invention selstes sponsive devices, 9

temperature controlling e 1 3E3 switch illustrated is similar to thatshown in eetueted e switch to en oo posit ol Earnes, Patent O- However,y 0011- An object of my invention is t0 trol invention will operate withother kinds (if molly adjustable eontrolliize device lei? e thermostaticswitches static switch whereoyfilie differences t is fi i t ated in Fgure 2, I W a thermotuire adjustments be obtained the lei-v staticswitch having a ease 20, a se member tempeeatore range tee spring memberisupporting an insulating Another objeet ALE-7 isf eition is to providebutton and two resilient conductin arms 23 teh e temperel, "rollingdevise o and 2 13 with contest points F35 and 26 respectively 339,5 Y og agtjgn. mounted thereon, My controlling device is also lmothey bj i; yai mmi l "1st1e,te{i in the Figure and is shown generally tempers-toreeomlo ill l 'ee "a The controlling device e ioesteci it most of itscomponent estemelly of the ease as as illusmember m is secured to thebase stay suite-isle means, such as by rivets 'eiil eesilieuteonfiuetine' arms elit it nipezstwe eoe switch W w button and are hasfew met nests, e other at their extreme o l Another object 01 myinvention to insuletins lilliieiisl @1081 18 s own is eontrolllng devicefor a, th tm Se 'e"e1enee character The contact points which is simplein construction to provide l. do not touch unless th y r constrainediecturing economy, by outside influence. e s illustrated in Figure 2,

Other nbjects and a, f ll r Lmder ta the arm is'iconneeteo. an outsideconductor invention may be had by referring to the follown the m it isConnected o an o t i e mg description and claims, taken in conjunctionwith the accompanying drawing n which: he Spring i $1915 V y owoefflcient Figure i is e side elevetional View e, theretotl'wlmalExpansion, Whemes b member has at very high coefficient of thermalefxpan- 021., Therefore, as the temperature of the sur-= dings of themembers Eli and 25 increases, use .1361 '5 tends to expand at a greaterrate w membeir ll. The result of this unequal expansion with increasingtemperature is that the insulatmg bottom is steadily lowered to- A s themember and the resilient conductarm is disposed to follow therealong. Ases the Contact members 25 and 26 are "*orcetl to touch one smother acurrent passes from we outside conductor 29 through the resilient E l,through the Contact point 25, into the conpoint 2;? and out through theresilient arm to the outside conductor 28. This flow of current ispossible as long as the resilient arms 23 through a, bushing andoontects a 11161 H and are close enough together to allow the of thethermostatic switch in which my Contact points and 26 to touch Ashereinis used; and b e described the resilient snn 23 is disposed to 8is a side View of the stem us 11love downwardly with each increase intempers, invention and illustrates a. extenom v t A? iollowing theinsulating button 22 and t 0 side thereof. esuse s disoonnectien betweenthe contact with reference to Figs? 1 of Iii ill points and at sometemperature as o'ecle stetie switch in which my controlling slew beused, with the top port of my device shown extending therefrom;

Figure 2 is a cross-sectional View knob of my invention;

li ig'ure proj-e ted. lew'o t. cam bushing used. in my jectecl 011 alist Figuxre 5 is s too View of elevetionel or emlwise my invention;

Figuie 6 is a, side View of es en. elevations enclwise eontrel in myinvention;

Figure 7/ is a top View of the stem termined by the position of theresilient arm 24 and its contact point 23.

My invention consists of a device to accurately control the position ofthe resilient arm 24. My invention is shown generally by the referencefigure 3| and consists of a holding jacket or sleeve 32, a slotted cambushing 33, a stem 34, and a control knob 35. An assembled controldevice of the type applying to my invention is shown illustrated inFigure 2 with the control knob 35 of the device positioned above anoutsidecase plate 38 of the appliance in which it is operating. The stem34 of my controlling device passes through an opening in the case 38,through the slotted cam bushing 33 which is positioned within theholding sleeve 32, and contacts the resilient arm 24.

The holding sleeve 32 has a circular opening therethrough of appropriatedimensions to accommodate the slotted cam bushing 33, and is secured tothe case 23 by any suitable means such as shown by peened tips or rim31.

The slotted cam bushing 35, which serves as a cam member may beconstructed from a fiat piece or material and rolled into shape forinsertion in the holding member 32. Figure 4 illustrates the slotted cambushing 33 in a fiat strip of material prior to being rolled into acylindrical sleeve and is provided with an opening 38 and a notch 39. Asnoted, in the illustration, the slot 38 is divided into three sections:A-C, C-B, B-D. The steep part of the slot 33 as shown in Figure 4 fromD-B, is to be used for giving the positive off-position movements, thesecond intermediate part of the slot as shown in Figure 4 from B to C isto be used for regulating the high range of temperature as for example,from cotton to silk when installed in an electric sadiron. A third partof the slot 33 as shown in Figure 4 from C to A is to be used for givingmore delicate adjustments of the lower heat range, as for syntheticfibers. The notch 33 is provided for convenience or holding the slottedcam bushing in a predetermined fixed position during assembly. Byrolling the strip of material, as shown in Figure 4, into a cylindricalform, a cylinder as illustrated in Figure 5 is pro duced. The cylinderas thus formed and described constitutes the slotted cam bushing 33.

An elevational view of the slotted cam bushing 33 as formed anddescribed is shown in Figure 6.

The stem '34 is composed of a hollow tube 43, an external tab'4l, anadjustment screw 42 and an insulating head 43. The tab 4| may beprovided by any convenient means, such as by pinching or squeezing apart of the external circumference of the tube 40 into the tab 4|. Theadjustment screw 42 is provided to adjust or initially calibrate theposition of the insulating bead 43 within the interior of the stem 34,so that the correct indications are given by the control knob or controldial.

A type of control knob which may be used with my invention is shownillustrated in Figure 3, and in cross-section in Figure 2. An uprightfin or rib portion 44 serves to provide a convenient finger tip grip,the circular part 45 is used as a convenient indicator on which to markvarious temperature ranges. A set screw and recess is provided, as shownat 41 of Figure 2, for the purpose of attaching the control knob 35 tothe stem part 34.

In the thermostatic switch such as illustrated generally by thereference character 20, if the temperature surroundingthe parts 2| and30 lowers, the button 22 carried on the part 2| is disposed to rise andpush the resilient arm 23 and the contact point 25 upward toward thecontact point 25 on the arm 24. At any temperature lower than thatrequired to bring the contact points 25 and 26 into contact, an excesspressure is caused by the raising of the insulating button 22.

The excess pressure thus produced is absorbed by bending of theresilient arm 23. Bending of the arm 23 causes no difference in theoperation of the thermostatic switch. Conversely, as the temperaturesurrounding the parts 2| and 33 increases, the insulating button 22 islowered and the resilient arm 23 follows therealong until contact isbroken between the contact points 23 and 26. Therefore, thermostaticcontrol of the temperature surrounding the parts 2| and 33 is maintainedby setting the position of the resilient arm 24 and the contact point 26thereon. From the description given it is seen that a fine adjustment ofthe temperature desired must of necessity be brought about by a fineadjustment of the resilient arm 24 and the contact point 23.Furthermore, whenever it is desired to assure complete separation of thecontact points 28 and 25 to completely remove the appliance from use, itis desirable to permit the resilient arm 24 to raise beyond any possiblecontact with the resilient arm 23.

For operation, my invention is installed on the thermostatic switch byfastening the holding jacket or sleeve 32 to the case 23 by means ofpeened tips or rims 31. The slotted cam bushing 33 is inserted withinthe opening of the holding jacket 32 and securely held therein. I preferto hold the cam bushing 33 in the holding jacket 32 by a snug, press fitbetween the parts. However, it is understood that these parts may bewelded, brazed, or fastened by other means to hold the cam bushing 33 inthe holding jacket 32. The stem part 34 is passed through the interiorof the slotted cam bushing 33 with the tab 4| guided into the slot 33thereof. The controlling knob 35 is secured to the upper end of the campart 34 by means of the side securing means 41. The insulating bead 43is inserted in the end of the stem 34 and is held in position by theforce exerted on it by the resilient arm 24.

In operation, the tab part 4| is positioned within the slot 33 of theslotted cam bushing 33 such that it will be at the position indicated bythe letter A within the slot as shown in Figure 4. When the tab 4| is inthe position described, the stem part 34 will be forced against theresilient arm 24 such that both stem 34 and the resilient arm 24 will bepositioned downwardly toward the resilient arm 23 a maximum distance.From this position only a slight cooling below the maximum temperaturefor which the thermostatic switch is designed will cause the insulatedbutton 22 to force the resilient arm 23 and the contact point 25 upwardenough to cause contact between the points 25 and 26, and thereby causereheating of the appliance in which the thermostatic switch isoperating. As the tab part 4| is moved circumierentially about theslotted cam bushing 33, that is, as the tab part 4| progresses from theposition as indicated by A in Figure 4 and along the slot 33 to theposition B as indi cated in the slot 38 on Figure 4, the stem part 34,the controlling knob 35, and the resilient arm 24 with its contactbutton 26 are disposed to rise away from the resilient arm 23. It isnoted, that the slot 38 slopes upwardly at a very slow rate between thereference characters A and C of Figure 4. The angle of-slope between Cand B is slightly more than the angle of slope between and C as shown inFigure 4.

Continuation of the slot 38 at the same angle of slope as the part ofthe slot between the points and B will not ordinarily provide enoughrise in the resilient arm 24 to give an off switch movement. Therefore,the steep part of the slot 38 from D to B serves to allow suddenmovement of the stem 34 and the control knob 85 under the spring actionof the resilient arm 24. The large endward or axial movement describedallows the contact point 26 to rise beyond any possible chance ofcontact with the point 25. Further, the described sudden and pronouncedendward or axial movement 01' the control knob 85 gives the user of theappliance complete psychological assurance that the iron or otherappliance is disconnected from the supply source.

To make adjustments oi temperature from the lowest temperatures forwhich the combination of the thermostatic switch controlling device isdesigned, an operator need merely turn the control knob 35 in such amanner that the tab part 4| is moved along the slotted part 38 of thecam bushing part 33 from the position marked A in Figure 4 through theposition marked C and on to the highest temperature position at thepoint marked B. A slight further movement of the control knob 35 pastthe position marked B in Figure 4 will bring the tab part 4| intoposition to be moved freely up the steeply sloping portion of the slot38. When the tab part 4| is in the oif position described, the springaction of the re silient arm 24 is free to move the stem part 34, andthe knob 35 upward with a sudden action for a distance far greater thanthe total distance moved as a result of the complete rotation of the tab4| from the position A to B within the slot 38. This sudden actionassures the user that the appliance is turned oil, and at the same timeallows the resilient arm 24 and its contact button 26 to be completelyremoved from all possible contact with the contact 25 of the resilientarm 23.

To return the appliance to use, the operator needs merely apply a smallamount of twisting action to the control knob 35. This small amount offorce will cause the tab to be deflected downwardly along the steep partof the slot 38 and pull the stem part 40 and the control knob 35therealong. The insulating bead 43 thus forces the resilient arm 24 withits contact point 26 downwardly and causes contact to be made betweenthe contact points 25 and 26.

Although I have described my invention with a certain degree ofparticularity, it is understood that the present disclosure has beenmade only by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

I claim as my invention:

1. A thermostatic switch comprising, first and second relatively movablecontact parts normally resiliently disposed to separate from each other,temperature responsive means to urge said first contact part againstsaid second contact part, substantially annular cam means supported relative to said contact parts, a control stem manually rotatable andaxially movable within said cam means to position said second contactpart in contactable relation with said first contact '6 part, said cammeans having a regulating on portion disposed at a slight angle withreference to a line normal to the longitudinal axis of the stem, saidcam means having a relieved of! portion disposed at a steep angle withreference to a line normal to othe axis or the stem, projecting meanscarried by said stem to cooperate with said cam means, said secondcontact part urging said stem axially of said cam means and holding saidprojecting means against said regulating fon portion of the cam meanswhen the stem is rotated to bring the said projecting means in alignmentwith the regulating on portion whereby turning of the stern regulatesthe position of the second contact part with respect to the firstcontact part, said stem thereby holding said second contact part incontactable relation with said first contact part, said second contactpart suddenly urging said stem axially of the cam means when the stem isrotated to bring the projecting means in alignment with the relieved"oil" portion of the cam means, said second contact part therebyresiliently moving away from contactable relation with said firstcontact part.

2. A switch comprising, first and second relatively movable contactparts normally resiliently disposed to separate from each other, supportmeans for supporting said contact parts, cam means carried by saidsupport means and disposed relative to said contact parts, a controlstem manually rotatable and movable endwise with reference to said cammeans for positioning said second contact part in contactable relationwith said first contact part, said cam means having a relieved offportion, projecting means carried by said stem to cooperate with saidcam means, said second contact suddenly urging said control stem endwisewith reference to said cam means when the control stem is rotated toalign the projecting means with the relieved off portion of the cammeans, said second contact part thereby resiliently moving away fromcontactable relation with said first contact part.

3. A switch comprising, a first contact part, a relatively movablesecond contact part normally resiliently disposed to separate from thefirst contact part, cam means supported relative to said second contactpart, a control stem manually rotatable and movable endwise with respectto said cam means for positioning said second contact part incontactable relation with said first contact part, said cam means havinga relieved oil portion, projecting means carried by said stem tocooperate with said cam means, said second contact part suddenly urgingsaid control stem endwise with reference to said cam means when thecontrol stem is rotated to align the projecting means with the relievedoff portion of the cam means, said second contact part therebyresiliently moving away from contactable relation with said firstcontact part.

4. A switch comprising, a first contact part, a relatively movablesecond contact part normally resiliently disposed to separate from thefirst contact part, support means for supporting said contact parts, acontrol stem manually operable and movable endwise with reference tosaid support means for positioning said second contact part incontactable relation with said first contact part, said support meansand said control stem having cam means and cam rider means, said cammeans having a relieved oi? portion, suddenly urging the reference tothe supaligned said second contact part control stem endwise with portmeans when the cam rider means is 7 8 fit-"n reiieved 0E portion of thecam means said seesnd csntast part thereby resilientiy mov UNITED STATESFATE E illg away {rem contactable relaticn with said first Number NameDye (JOHN-8t p 2 185 814 Kuhn Jan 19% RICHARD JORDAN- 5 2,248,666Fischer July 3,1941 7 1,985,100 Kuhn et a1 Dec. 18, 1934 RFFERENEESCITED 2,158,857 Hall at B1 May 16,1939

The fnliswing references are 01 reccrd in the file at this mtent:

